This release is available in
German.
We are surrounded by microorganisms. They inhabit our skin, the
air we breathe, the surfaces we touch. In most cases this is not a
problem, but there are situations in which these constant
companions can be dangerous or even life-threatening. They are
unwelcome, for example, on medical instruments, in culture fluids
or on laboratory-grown tissue transplants such as cartilage.
Constant sterility checks are therefore required during the
production of artificial cartilage. Conventional testing methods
for detecting germs are, however, time-consuming. Specimens have to
be taken and then cultivated and reproduced in culture fluid
because bacteria and fungi can only be detected in large
quantities.
Research scientists at the Fraunhofer Institute for Physical
Measurement Techniques (IPM) in Freiburg, working in collaboration
with the Fraunhofer Institute for Interfacial Engineering and
Biotechnology (IGB) and the Fraunhofer Institute for Biomedical
Engineering (IBMT), have succeeded in drastically shortening this
process. Within just a few hours the experts can identify
contaminations; one single germ is enough. »Using
conventional methods it takes up to two weeks to test the purity of
specimens, for example autologous tissue grown in a culture medium.
The patient is given an implant although the sterility check has
not been completed,« explains Carsten Bolwien, project
manager at the IPM. »With our automated Raman system we can
check specimens immediately before they are implanted. We tested
this on artificial knee cartilage. Our device combines a microscope
with a Raman spectrometer. The aqueous solution containing the
piece of cartilage is first filtered through a micromembrane. Only
particles exhibiting a suspicious size are trapped in the tiny
holes of the micromembrane, and we examine them spectroscopically.
In comparison with the known spectra the Raman spectra enable the
particles to be identified and contaminations by bacteria or fungi
can be detected.«
A demonstration Raman spectrometer has already been built and
can be seen at the Analytica trade show in Munich from March 23 to
26 (Hall A1, Stand 471). Initial blind tests checked by health
agencies are scheduled to take place this year. The research
scientists will examine artificially infected cartilage cultures
and detect the contaminations. If everything goes well, the testing
method will be officially approved.
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